Health and Function of Gastrointestinal Tract as Influenced by Dietary Immunomodulatory Components in Poultry

Saheed Osho, Purdue University

Abstract

Experiments were conducted to investigate the efficacy of soybean bioactive peptide and chitosan oligosaccharide on a stress and disease challenge model. For the first study, responses of broiler chickens (Cobb 500) to graded concentrations of dietary soybean bioactive peptide (SBP) (0, 1, 2, 3, 4, 5 g of SBP/kg of diet) and coccidia challenge (CC) were investigated. In Experiment 1, 384 male broiler chicks were used to investigate the effect of graded dietary concentrations of SBP in a randomized complete block design. There were linear effects (P < 0.05) of graded concentrations of SBP on BW, BW gain, gain:feed, ileal villus height and jejunal crypt depth at d 22 post hatch. There were linear effects (P < 0.01) of graded SBP concentrations on ileal dry matter and energy digestibility. Experiment 2 was conducted to investigate the immune-protective properties of SBP during a coccidia challenge. Dietary SBP ameliorated the CC-induced effect (P = 0.01) on gain:feed. Coccidia challenge reduced (P < 0.05) jejunal villi height whereas dietary SBP supplementation increased (P < 0.05) jejunal villi height. Dietary SBP attenuated the CCinduced effects (P < 0.05) on the expression of plasma interleukin-1β, transforming growth factorβ, claudin-1 and occludin genes. The second study examined the response of broiler chickens (Cobb 500) to graded dietary concentrations of dietary chitosan oligosaccharide (COS) (0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 g of COS/kg of diet) and coccidia challenge (CC). Experiment 1 was conducted to investigate the effect of graded dietary concentration of COS in a randomized complete block design. There were linear effects (P < 0.05) of graded COS concentration on body weight (BW), BW gain, feed intake, jejunal villus height and villus height to crypt depth ratio at d 22 post hatch. Between 0.50 and 1.18 g COS/kg diet was optimum for BW gain, jejunal villus height, and villus height to crypt depth ratio. There were linear increases (P < 0.05) in ileal dry matter and energy digestibility. Experiment 2 was conducted to investigate the immune-protective properties of COS on broiler chickens during CC. Coccidia challenge reduced (P < 0.05) and dietary COS increased (P < 0.05) BW gain, and feed intake. Dietary COS mitigated (P < 0.05) the CC-induced effects (P < 0.05) on gain:feed. Coccidia challenge reduced (P < 0.05) jejunal villus height whereas dietary COS supplementation increased (P < 0.05) jejunal villus height. Dietary COS supplementation attenuated the CC-induced effects (P < 0.05) on the expression of plasma interleukin-6 and 10, claudin-1 and occludin genes. Next, a study was conducted to investigate the effect of dietary chitosan oligosaccharide (COS) on growth performance, nutrient digestibility, jejunal morphology, gene expression, and plasma antioxidant enzymes in male broiler chickens under experimentally induced stress via infeed dexamethasone (DEX). The results showed that dietary COS also decreased (P < 0.05) DEXinduced effects (interaction; P < 0.05) on BW, BW gain, and gain:feed. Dietary COS supplementation attenuated the DEX effects (interaction; P < 0.05) on villus height, crypt depth, villus height to crypt depth ratio, and ileal digestibility of DM and energy. The DEX-induced effect of relative mRNA expression of jejunal mucosa IL-6, IL-10, and claudin-1 was reduced by dietary COS supplementation (interaction; P < 0.05). Responses (interaction; P < 0.05) in the activity of plasma superoxide dismutase, catalase, and glutathione peroxidase to COS and DEX were similar to that observed with the relative mRNA expression. Chitosan oligosaccharide supplementation increased (P < 0.05) the mRNA expression of IL-8 and occludin. In the final experiment, the objectives of this study were to determine the effect of dietary supplementation of garlic-derived diallyl disulfide (DADS) and diallyl trisulfide (DATS) on growth performance, gut morphology, and cecal microflora in broiler chickens. Dietary concentrations of garlic-derived DADS + DATS between 0 and 75 mg/kg had no effect (P > 0.05)on growth performance and gut morphological responses examined. There was a quadratic effect (P < 0.05) of DADS + DATS on log10 number of copies of cecal Escherichia coli at d 8 post hatching. However, Lactobacillus spp log10 number of counts were not affected by dietary supplementation of garlic derived DADS + DATS.

Degree

Ph.D.

Advisors

Adeola, Purdue University.

Subject Area

Animal sciences|Parasitology

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